Shotshell Pressure Testing Results

[Cold Spring]

The current maximum average pressure permitted by SAAMI for 12g/2-3/4" loads is 11,500 psi. Anyone buying commercial 12-gauge shotgun ammo that's made for a wide range of guns to include semi-autos should expect them to be loaded to about that max pressure average. CIP (Euro) max average pressure is just a little lower.

Craig, the velocity shown for those 10g/1-5/8 oz/2-7/8" progressive powder loads is comparable with specs when they were introduced.

[Drew Hause]

Thank you for sharing Jim, and I added the numbers here
https://docs.google.com/document/d/1...U/edit?tab=t.0

In a 1927 Western Cartridge Co. flyer “Super-X The Long Range Load” by Capt. Chas. Askins, the Super-X 10g 1 5/8 oz. “about 4 1/2 Drams” (DuPont Oval) No. 2 shot Full choke 32” barrel, average velocity over 40 yds. 1030 fps; “up to 13,000 psi” by crushers = about 14,500 psi by modern transducers.

Some time ago Armbrust ballistic tested some loads from the 30s and found the results to be inconsistent; he felt from primer rather than powder degradation.
It's possible that those shells when fresh might have run higher pressures.